BURNABY, British Columbia, June 23 (UPI) -- Researchers are just now understanding the ecological consequences of the massive 2013 die-off of sea stars along North America's Pacific Coast, and the findings aren't good.
The loss of sea stars along the West Coast as a result of wasting disease was one of the largest die-offs in recent decades. A new study by marine scientists at Simon Fraser University suggests the mortality event had an ecological domino effect, affecting biodiversity and abundance in local ecosystems.
Scientists specifically looked at the decline of sunflower sea stars in Howe Sound, a series of interconnected fjords connected to the Strait of Georgia just northwest of Vancouver, British Colombia.
"Howe Sound lost nearly 90 percent of its sunflower stars in a matter of weeks," Jessica Schultz, a grad student at SFU and Vancouver Aquarium's Howe Sound research program manager, said in a news release.
Underwater surveys showed that the population of sea urchins, a favorite food of sunflower stars, quadrupled in the two years following the die-off. As a result, kelp, a favorite food of sea urchins, declined by 80 percent.
"This is a very clear example of a trophic cascade, which is an ecological domino effect triggered by changes at the end of a food chain," said Isabelle Côté, a marine ecologist at SFU.
Researchers expect the domino effect to remain apparent, with sea urchin populations growing and kelp volume declining, until sunflower stars make a comeback.